Hubble Space Telescope Servicing: A Case Study in Analysis and Presentation of Space Program Risk Information Vicky

1. 1 Hubble Space Telescope Servicing: A Case Study in Analysis and Presentation of Space Program Risk InformationVicky HwaDavid BeardenJack Maguire April 16, 2008

2. 2 Background Safety concerns surrounded the loss of the Space Shuttle Columbia and crew In mid-2004 NASA cancelled the Hubble Space Telescope (HST) Shuttle Servicing Mission 4 (SM4) previously planned for 2005 Analysis at this time indicated that without servicing, HST would begin degrading, likely expiring in 2009 Estimates based on HST reliability models and battery studies NASA embarked the development of other options to service HST As part of a decision-making process, NASA Headquarters (HQ) requested a non-advocate review of HST servicing alternatives

3. 3 Decision Makers and Stakeholders NASA Administrator NASA Comptroller NASA Chief Engineer NASA Associate Administrator, Exploration Mission Systems Directorate (ESMD) NASA Associate Administrator, Science Mission Directorate (SMD) NASA/Goddard Space Flight Center (GSFC) Hubble Space Telescope Program Office NASA Independent Program Assessment Office (IPAO) NASA Engineering & Safety Center (NESC) National Academy of Sciences (NAS) Science Community Congress � House Science Subcommittee

4. 4 Situation in mid 2004 NASA examined options for Hubble Space Telescope servicing without Shuttle Extend mission life without servicing Provide the capability to safely and reliably de-orbit Hubble Space Telescope (HST) at the end of its useful scientific life Provide the capability to robotically extend the scientific life of HST for a minimum of 3 years Enhance scientific capability with new instruments GSFC developed baseline concept to study feasibility of robotic servicing mission & Request for Proposal (RFP) to industry IPAO/NESC Technical Feasibility Study to assess technical feasibility, cost, schedule of GSFC concept National Academy of Sciences (NAS) Study Aerospace Corp. Analyses of Alternatives Study

5. 5 Alternatives Study Overview Risk assessment of Hubble Space Telescope (HST) servicing alternatives Alternatives that encompassed a range of options from safe disposal to re-hosting capability on other spacecraft For each alternative assessed: (a) cost and schedule; (b) risk and safety, and (c) capability relative to HST post-SM4 state Study Scope Nine week study: June 2004 - Aug 2004 Level-of-detail scaled according to available data and schedule Needed to convey aggregate risk information to decision makers Include HST science and technical communities Status to and feedback from stakeholders on alternative concepts and Measures of Effectiveness (MOEs) Implications of capability impact on science Accurate data on HST technical constraints, operational state

6. 6 Hubble Space Telescope Configuration

7. 7 Robotic Servicing Decision Tree

8. 8 Approach The general approach was similar to an Independent Program Assessment but due to the time constraint was less rigorous.The general approach was similar to an Independent Program Assessment but due to the time constraint was less rigorous.

9. 9 Alternatives Development Goal Represent range of variation in cost, schedule and risk Sufficiently broad to �cover� most concepts �out there� Emphasize robotic concepts Methodology Identify spectrum of alternatives (brainstorming and methodically) Down-select to a handful of representative concepts Define selected alternatives (concept of design, concept of operations, timeline) Down-select Criteria Reasonable coverage of trade space including: lowest cost, least impact to HST, most complex, etc. Not an exhaustive coverage of every variation - bounding cases Inclusion of a concept did not imply feasibility or endorsement

10. 10 Alternatives Assessed

11. 11 Alternatives Families Extension of HST science through non-servicing means A1: Existing HST configuration A2: Rehost in LEO A3: Rehost outside LEO Robotic Missions B1: Disposal B2: Servicing (Life Extension Only) with Separate Disposal Mission B3: Combined Servicing (Instruments and Life Extension) B4: Servicing (Instruments and Life Extension) and Attach Later for Disposal Other Missions C1: Tug to ISS C2: Safe Haven D1: SM4

12. 12 Summary of 21 Alternatives

13. 13 Disposal, Servicing Alternative Configurations

14. 14 Rehost, Other Alternative Configurations

15. 15 Measures of Effectiveness (MOEs) MOE Categories Cost and Schedule Risk and Safety Capability MOEs Cost Life Cycle Cost (FY04$B) Schedule Nominal Development Time (Months) Development Risk Probability of HST in Required State (%) Mission Risk Probability of Full Mission Success (%) Capability Capability Relative to Post-SM4 HST

16. 16 Cost & Schedule Methodology

17. 17 Risk & Safety Methodology 3. Development Risk Risk related to the ability to execute the program on a schedule compatible with the degradation of the HST 4. Mission Risk Risk related to the ability to successfully and safely execute the defined mission, including 3 years of science operations Disposal

18. 18 Capability Assessment Methodology

19. 19 MOE 1: Life Cycle Cost

20. 20 MOE 2 & 3: Schedule & Development Risk

21. 21 MOE 4: Mission Success

22. 22 MOE 5: Capability Relative to Post-SM4 HST

23. 23 Expected Value vs. Life Cycle Cost

24. 24 Findings A de-orbit mission is technically and programmatically feasible by earliest re-entry date Suitable robotic docking technologies demonstrated in other programs All propulsive re-entry options reduce casualty expectation to zero A robotic servicing and de-orbit mission is high risk HST likely to fall into unserviceable state before robotic servicer could arrive High mission risk due to unprecedented operations and unproven technology Separate servicing and de-orbit missions provide flexibility however, even a minimal servicing mission has high development risk Re-host options are technically and programmatically feasible However, there will be a 2-7 year gap in science return, between when HST ceases science operations and a new program can come on line New observatory program would likely compete with ongoing and future observatories for funding Astronaut servicing provides highest value and continuity with manageable risk

25. 25 Conclusion Critical assessment that robotic servicing mission: (1) could not be developed in time before HST would lapse into a non-serviceable state; and (2) would undertake unprecedented servicing operations Key to success of process was ability to work closely and transparently with internal and external constituencies with varying agendas Analysis received unusual visibility, scrutiny and interest at the highest levels of the Government culminating in testimony before the National Academy of Science and Congress Risk information presented in an effective way that immediately conveyed many complex inter-related factors Contributed to decision to abandon robotic means and put Shuttle servicing back on the table Currently targeting August 2008 for fifth (final) space shuttle servicing mission to HST to extend capabilities through 2013 including first ever on-orbit repair of two existing instruments: Space Telescope Imaging Spectrograph (STIS) and Advanced Cameras for Surveys (ACS)